


The A city skirmish

by Iarinthel



Category: Mass Effect Trilogy, ワンパンマン | One-Punch Man
Genre: Crossover
Language: English
Status: In-Progress
Published: 2020-05-07
Updated: 2020-05-08
Packaged: 2021-03-03 05:20:16
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 2,593
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24059617
Author URL: https://archiveofourown.org/users/Iarinthel/pseuds/Iarinthel
Summary: Saitama and Genos find new enemies and allies in A city.
Comments: 4
Kudos: 6





	1. Chapter 1

**Author's Note:**

> this thing has been on my phone for literal years, I’m mostly posting this just to have somewhere to link my fic in
> 
> I haven’t written an update for this in years either, but if enough interest is shown I might write more
> 
> maybe
> 
> plz enjoy

In his time as a superhero, both registered and unregistered, Saitama has seen many different types of monsters and villains preying on the weak. He's fought a number of them, killed many, left a few alive, to save the day. It's gotten to the point that he thought nothing could surprise him anymore.

This is the first time he's ever had to deal with a situation like this though.

"Help!"

"Monsters!"

"Save me!"

The citizens of A city wailed in fear as unfamiliar monsters descended on them, intent on death and destruction. An ear piercing scream echoed in the air, as a long limbed monster with tentacles on its head teleported with a loud CRACK right next to a crying child. Before he could jump into the fight, a booming BANG was the only indication of a masked woman arriving to take the child in her arms and running away from the monster, who screeched in what seems to be frustration. It left her vulnerable to a large orange shield smacking her from behind as another armoured stranger joined the battle, who dodged the claws with practiced ease and retaliating with a cold wind emanating from orange gauntlets on his arms.

An explosion of ice emanating from the monster was how the next stranger entered the scene before he brought out a sword and swung at the monster with a wordless cry. It staggered the monster momentarily, making it bleed purple blood from a large gash on the back of its legs, which only served to turn its attention to him. As it clawed at him, he teleported backwards with a crack and blue fire to dodge, only to be replaced by the masked woman from earlier shooting a gun with steady hands and good aim. When the monster turned towards her, she threw off its attack with a wave of her hand and an explosion of blue lightning that he could feel in his bones metres away. It also threw off a number of benches and trees from the sidewalk they are fighting on, cracking under the force of the explosion.

Only seconds after another armoured stranger made herself known, by slashing at its back with a sword before flipping away from retaliation. This armoured stranger brought out a gun locked onto the back of her hips and shot at the monster from the back of a bench, sometimes disappearing into thin air only to materialize behind the monster in opportune moments like after another explosion had staggered it. At other times she'll flip acrobatically to fire a wave of lightning at the monster from her sword to ward off the mechanical zombies and set off explosions of ice and fire on the tentacled monster. Her focus seemed to be to support the other two as they kept the monster's attention on themselves and off the civilians fleeing the area.

Once the tentacle head monster died screaming, more came out. Something large, clawed and armoured showing an exposed neck and spine holding up a head with a fringe with what looked like mandibles, staring soullessly out of glowing red eyes, lumbered forward. It was followed by something with the same head on a two legged creature holding a gun in its hands, but it looked like an alien with its large collarbone, tiny waist, three fingers and two toes on legs that's bent backwards like a dog. Mostly it shot at the team while the large one would charge at them or smack its claw on the ground, though sometimes it stands still while a red glowing material floated from it to one of the human corpses or the four eyed monsters. That left it vulnerable to a shot in the head, more often than not, along with whichever other monster floated helplessly in midair.

He watched with mild interest as the group harassed the large clawed monster with gunfire and explosions, dodging its charge with casual ease, only pausing to reload their guns. It died in a blaze of blue fire as the masked woman and the man with a sword coordinated their attacks on it, leaving its mangled corpse to rot as they dealt with the rest of the horde.

The strange zombie monsters made with a mix of human corpses covered in metal parts swarm the group, which usually only resulted in even more explosions and a gorey end. There were also a few four eyed lumpy things that shot out of an arm which looked like it was made with a human corpse, though they usually died at a further range than the others. Sometimes, if one of their own died, the four eyed monsters would run up to the corpse and start eating it, leaving them vulnerable to all kinds of attacks. A number died riddled with the strange glowing projectiles from their guns, some others destroyed in an explosion of fire and ice. Some were just punched into a wall, while others were slashed from behind or lost their heads. None survived.

There were two others wearing the same uniform, another woman wearing a lot of pockets and a man glowing in red with rockets launching from his right shoulder. They were more focused on evacuating the civilians in a calm and orderly fashion, keeping the enemies' focus on them rather than the people screaming in fear when some of the monsters manage to sneak past the other four. They barricaded the only exit with benches and broken debris, making sure that none of the monsters get past their guns and grenades. Every once in awhile one of the other four would pass off another civilian before getting back into the fight, always making sure that there were less enemies for them to deal with on their way.

It was clear that the team was very experienced fighting the new enemies. The seamless way they fought together and set off explosions was too practiced for them _not_ to be. They had flawless teamwork that made heroes in the Association look like unprofessional amateurs. They also wear the same colours on their armour, mostly black with a red stripe surrounded by two white stripes running down their right shoulders and arms. Each of them also have something written in English on their chest, an "N7" with a red triangle on their left pectoral/breast. It made them seem like trained operatives, like policemen or soldiers fighting a war. They were certainly professional enough about fighting monsters, as if they were trained to fight things that would give normal people nightmares just by existing.

"Sensei."

"Genos."

"Who are they?"

"Don't know."

"Shouldn't we help them?"

"...Doesn't look like they need help fighting."

"But-!"

"The two at the barricades look like they need help evacuating people though."

"Yes!"

"Let's go."

"Right!"


	2. Chapter 2

"Oi. Need help?"

Not surprisingly, the two at the barricades were jumpy after fighting for as long as they have. Having the barrel of a gun pointed at you isn't a great way to be greeted, though thankfully they weren't fired at. He's seen the kind of aim these people have and although he's not sure it would kill him it would probably still be painful. Genos surprisingly hadn't returned fire, though he was intensely focused on the two in a way he hasn't seen since they sparred that one time.

"[Who are you two?]"

"[And what are you doing here?]"

"Uh..."

They didn't seem to speak Japanese, which was unfortunate because he hadn't been good at learning English. Never mind being able to hold a conversation in it.

"[I am (Genos), and this is my teacher (Saitama). We would like to assist however we can.]"

He hadn't known that Genos could speak English so fluently, but he won't complain. It's certainly coming in handy now. He only understood his name and Genos had been said, so he nodded along when Genos finished talking as a show of solidarity with whatever he had told her. If he had to guess, he just introduced both of them.

"[Really?]"

"[We do need the help.]"

"[The others need to know about this.]"

"[Comm them. I'll brief the civilians on what they can do to help.]"

"[Fine.]"

The man put two fingers by his right ear while the woman stood up and turned around to face them fully. She was shorter than Saitama by a few centimetres but the way she held herself made her seem taller than Genos, with a confidence that must've been earned from however long they fought the monsters for. With the ease they fought, it must have been quite some time. It reminded him of some of the S class heroes, the ones who were more quiet about their deeds and heroism like Bang.

"[We stay here at the barricade and make sure none of the Reapers escape. Don't want any Husks or Cannibals getting into other parts of the city. It would be chaos. Thankfully we've just dealt with all the Banshees and Brutes, making this entire wave easier to handle on our own.]"

"[Husks? Cannibals? Banshees? Brutes?]"

"[Husks are the ones that look like zombies made with synthetic parts. Cannibals are the ones with fours eyes and a gun arm. Watch out for them, they like to sneak up on people. The Banshee was the one that screams a lot and has really long limbs. Brutes are the big guys with metal claws that tend to charge at everything in sight.]"

"[You call them Reapers?]"

"[If they have a name they prefer to call themselves, I certainly haven't heard of it. We call them Reapers because that's what Commander Shepard called them. It seems an appropriate enough term.]"

"[As you say.]"

"[Do you have a gun?]"

"[No. We would need a license to use one in the city.]"

"[Okay then. Can you fight?]"

"[Yes.]"

"[Then you two are on watch. Make sure there's no Reapers trying to sneak behind us, and if there are civilians keep them away from the thick of things. We don't need more casualties.]"

"[Understood.]"

"[Tell your teacher to be careful with that cloak of his. Husks like to grab at people and that thing can be used against him in a fight.]"

"[I will.]"

With a nod she signalled the end their conversation, turning back to her comrade who seems to have finished with whatever it was he had been doing. Genos turned to him, with a warning and instructions on what they need to do.

"We're on watch. We need to look out for sneaky enemies and keep the civilians safe."

"Alright."

"She says to be careful with your cloak, sensei. It can be used against you."

"Oh? I guess that makes sense. I'll take it off then."

Wearing only the yellow suit without the cloak feels odd, after wearing the entire ensemble for so long, but it can't be helped. The woman is probably right. He's seen the way the weird mech zombies grapple at people and he doesn't want them to rip it.

"[They know what they're doing?]"

"[We do.]"

"[Stay out of the line of fire, and keep yourselves safe. Thankfully, this is the last wave of Reapers so we should be finished soon.]"

"[Right.]"

"[We getting evac after this?]"

"[Probably not.]"

"[Damn.]"

"[We'll worry about that later. There's Reapers that need killing and we don't want to miss out on the fun.]"

"[Heh. Right. Definitely don't want that.]"

It was one of the smoothest operations that they'd ever taken part in. They worked well with the other 6, better than they'd expected. Clearly this wasn't their first time evacuating fleeing civilians from the field of battle, since they were able to account for most situations as well as being able to adapt to Saitama and Genos' presence on the field. Genos learned that he can make some of the explosions with his incinerators with the one that throws EMP grenades and the one that uses a large orange shield, while Saitama uses his speed to escape with as many civilians as he can, only fighting when he absolutely has no other option. It was an interesting experience for the two of them, fighting with a team instead of just jumping into the fray like they normally would.

It felt like hours before the monsters were all killed, though it likely wasn't much longer than a few minutes, and in that time Genos was clearly itching for a notebook to write things down in. He watched the entire battle with an intensity that was unusual even for him, eyes wide and recording as much as he was able. Saitama was a little bored being the designated herder but he also felt accomplished every time he helped one more civilian escape. It wasn't the same kind of rush he'd get when fighting villains and monsters himself but it was a pleasant sensation. The children he helped were very thankful, which improved his mood dramatically. Only after the last Husk died did the N7s finally say something that wasn't a warning of another incoming enemy.

"[Hey you, with the synthetic arms. Not bad.]"

"[...Are you talking to me?]"

"[His name is (Genos), Paladin.]"

"[That's a weird name.]

She only shook her head in exasperation as the masked woman spoke to Genos.

"[Your teacher did a great job evacuating the civilians.]"

"[He was very calm and good at dealing with the panicking children.]"

"[Not many people can keep their heads when getting attacked by Reapers and helping others escape. Not as fast he did.]"

"[Impressive.]"

"[Can he even understand what we're saying?]"

"[No. Sensei only speaks Japanese.]"

"[Shame.]"

"[Well tell him thanks for us.]"

"[And that we're more than willing to fight alongside him again.]"

"[I will.]"

The sound of wailing sirens filled the air as police cars surrounded the area. Police officers poured out with guns in hand pointed at the armoured strangers as they screamed,

"Police! Put your hands where we can see them!"

"Officer-"

"Demon Cyborg, please stand back."

"[Demon cyborg?]"

Laughter could be heard from one of the armoured N7s. "[What a great alias.]"

"[Hey, we're all cyborgs too. Think we can get some cool alias like that too?]"

"[You have a pretty cool alias already, Fury.]"

"[Not as cool as yours, Demolisher.]"

"[I'll stick to Slayer.]"

"[It makes you sound like something out of a pre-space flight vid.]"

"[That's rich coming from you, Destroyer.]"

“[Someone with a sobriquet of Paladin has no leg to stand on.]”

“[Irrelevant.]”

“[Well of course you’d say that, Shadow.]”

"[I think we're getting a little distracted here.]"

"[Maybe a little.]"

Saitama tilted his head as he watched the previously professional group devolve into what sounds like a very immature argument.

"Oi, Genos. Can they understand us?"

"It seems that way, sensei."

"Huh."

The woman with too many pockets turned to Genos.

"[(Genos), would you be so kind as to be our interpreter?]"

"[If you wish.]"

"[Thank you.]"

"[Ey, (Genos). Can you tell the officers to put the guns away? I'm getting twitchy being at the barrel of a gun.]"

"Officers, you should put your guns away."

"Only if they put theirs away first."

"[That seems fair.]"

"I don't need a gun to kill someone.]"

"[ _Slayer_.]"

"[Oh fine.]"

The armoured strangers put their respective weapons away, with audible clicks as it locked onto their armour in a collapsed form. Slowly the police officers surrounding them also started holstering their guns, when suddenly the sound of helicopter blades echoed loudly in the air, followed by someone's voice.

A very familiar voice.

**Author's Note:**

> that’s about all I wrote on my phone
> 
> hope you enjoyed


End file.
